Good day, amandawp.
I appreciate the detailed information you provided about your migration issues.
I've got two options on how you can bring into QuickBooks Desktop Pro your missing invoices.
You may enter them manually into the system. Or look for a third-party application to import missing invoices.
Also, I'm adding this article about the limitations when converting QBDT to QBO: What to expect when you switch from QuickBooks Desktop to QuickBooks Online.
Feel free to get back into this thread if you have other questions. The Community is here to help.
